This invention relates to the printing of lenticular materials, and more particularly, to a guide such as an idler roll or impression roll installed on a printing press and formed for use in guiding a sheet of lenticular material through the printing press. The guide roll eliminates lateral movement of the lenticular material as it moves through the press so, and other possible distortion of the web, to enhance the quality of the resulting printed materials.
In U.S. patent application Ser, No. 09/082,715, now U.S. pat. No. 5,967,032, the teachings of which are incorporated herein by reference, there is described a printing process for flexographic printing of a thin sheet lenticular material. As noted therein at page 3, lines 21-23, "the quality of a printing operation has been found to be best controlled by meticulously controlling the alignment of the film, printing plates, and lens material prior to the start of printing". Once a printing operation has begun, it is important to maintain the alignment so meticulously established during the set-up phase of the process. As described in the co-pending application, alignment aids are incorporated in the printed materials to aid the printer in maintaining alignment
One cause of misalignment during a press run is lateral shifting of the web of lenticular material as it moves through the press. As is well-known in the art, the web of material traverses between an idler roll and an impression roll at each station along the press where a color is printed on the flat side of the web. Even minute sideways movement of the web which occurs, for example, due to vibrations, can significantly effect print quality. Another cause of run misalignment results from tension on the web as it moves through the press. The web material is plastic and is deformable by forces exerted on the web. The printing plates mounted on the press to print the images viewed through the lenticular material are produced using prepress materials whose dimensions conform to those of the unstressed lenticular material. Distortions in the web dimensions, as the web runs through the press, therefore also results in distortions in the printed product.
The present invention offers a solution to these problems which is both cost effective and readily implemented, so to further help produce high quality printed materials.